Ignition system for internal combustion engines



June 15, 1965 s. ANDERSEN 3,189,009

IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed Jan. 18, 1963 INVENTOR $71 6- ANDERSEN QMM I ATTORNE Y8 United States Patent Oflice Patented June 15, 1965 51/6 6 Claims. (Cl. 123-41) This invention relates to ignition systems for internal combustion engines and is more specifically, though not exclusively, concerned with ignition systems for twostroke piston engines.

One object of the invention is to provide an ignition system by means of which the direction of rotation of the engine may be easily and rapidly reversed at will.

Another object is to provide an ignition system by means of which the direction of rotation of the engine may be reversed at will without the engine parts being subjected to undue stresses.

' Another object is to provide an ignition system which will provide for easy manual starting of the engine.

Briefly, the principle of the invention is based on the fact that, when the ignition in the cylinder, or cylinders, of a piston engine is discontinued, e.g., by short-circuiting the ignition coil of petrol engines or by interrupting the fuel injection in diesel engines, the engine will continue to rotate for a short time while still taking in and compressing air of fuel mixture, until the inertia of the moving parts becomes too small to overcome the pressure of the compressed air in the cylinder or cylinders when the pistons or a piston, approaches its topmost position. The engine will then come to a standstill with a small backward movement of the piston and the crankshaft. In accordance with this invention, this backward stroke of the engine is utilized for provoking an ignition which will start the engine again in the reverse direction, if provison has been made for ensuring continued ignition at the right point of the piston stroke during this reverse rotation.

Such backward stroke of the piston may also be proyoked manually in an engine which is to be started, by turning the crankshaft through a small angle to cause the piston, or one of the pistons of the engine to compress air in its cylinder, and then releasing the crankshaft. In this case the device of this invention may, accordingly, [be utilized for starting the engine without the necessity of manually overcoming the compressive forces in the cylinder, or cylinders.

The invention will not be described in great-er detail, reference being had to the drawing, in which:

FIG. 1 is a schematic view of the essential parts of one form of an ignition system in accordance with this invention for use in a single cylinder two-stroke engine, and

FIG. 2 is a view at right angles to FIG. 1 showing one end of the crankshaft of the engine and the parts co-operrating therewith.

In the following description, the single cylinder twostroke engine itself will not be described, since it may be of any well-known type and construction. The engine being adapted for rotation in either direction, as required, it is provided with two circuit breakers 1 and 2 for the ignition circuit, one for each direction of rotation, as indicated by arrows in FIG. 1. These circuit breakers 1 .and 2 cooperate with a cam 3 secured to one end of the crankshaft 4 of the engine. One contact of each circuit breaker 1 or 2 is grounded while the other is adapted to be connected to the primary windings of an induction coil 5 by means of a manually operable switch 6 so that the coil may be connected at will through leads 8 and 9, respectively, to either of the two circuit breakers 1 and 2.

The induction coil is, as is well-known in the art, connected with a source of voltage (not shown) and a spark plug 7, a condenser 10 being provided for eliminating sparks at the circuit breakers 1 and 2. So far, the device described is known per se.

A switch or double-acting circuit breaker 1d is connected in parallel with the circuit breakers, the switch 11 having stationary contacts 12 and 13 connected with leads 8 and 9, respectively, and a contact arm 14 mounted coaxially with the crankshaft 4 for pivoting movement between contacts 12 and 16. To this effect, the contact arm 14 is secured to a short axle or trunnion 15, which is mounted in a suitable stationary part 16 of the engine coaxially with the crankshaft 4 and provided with a friction disc 17. A coil spring 18 acts to hold the friction disc 17 against the adjacent end face of the cam shaft,

under a suitable light pressure so that, when the crankshaft is rotating in a predetermined direction, the contact arm 14 is frictionally rotated in the same direction, until it abuts against the corresponding contact 12 or 13, as the case may be, and held in engagement with this contact as long as the rotation continues.

The operation of the device described is as follows:

Assuming that the crankshaft is rotating in a clockwise direction, as seen in FIG. 1, then the switch or preselector 6 mus-t be connected to the lead 8 in order to ensure the required ignition by means of the circuit breaker 1. The rotating crank-shaft holds the contact arm 14 of the automatic switch 11 frict-ionally against the contact 13, whereby so far no effect is produced. If it is now desired to reverse the direction of rotation of the engine, it is only necessary to shift the switch 6 from lead 8 to lead 9. Hereby the induction coil will be permanently grounded over lead 9, con-tact 13 and contact arm 14 as long as the engine continues to rotate in a clockwise direction. However, no sparks being now produced by the spark plug 7, the engine will gradually cease to rotate and finally effect a small backward stroke in .a counter-clockwise direction under the action of the air compressed in the cylinder. This small counter-clockwise rotation of the crankshaft 4 is sufficient to swing the contact arm 14 from the contact 13 to the contact 12, thereby breaking the induction coil circuit so that a spark is produced by the spark plug 7. This spark ignites the still suflicien-tly compressed fuel mixture in the cylinder so that a combustion takes place which causes the piston to positively drive the crankshaft in a counter-clockwise direction so that the engine is started in this direction, ignition being now controlled by the circuit breaker 2. It should be noted that this reversing operation does not require the throttle of the engine tobe more or less closed, since the stopping and re-starting of the engine is effected solely by provisionally discontinuing ignition by means of the switch 6 and recommencing it at the proper moment by means of the automatic switch 11. Thus, reversal of the direction of rotation of the engine may be effected with the throttle fully open, and still no part of the engine will be subjected to undue stresses, since the engine is allowed to come almost to a complete standstill before it is restarted in the reverse direction.

It will be evident that the device described may also be utilized for starting the engine from a standstill. To this effect, it is only necessary to select the required direction of rotation by means of the preselector switch 6, and to rock the crankshaft 4 to and fro a couple of times to fill the cylinder with fuel mixture, until the engine starts of its own accord. The running direction will always be that selected by means of the preselector since no starting spark will be produced except when the crankshaft is turning in the required direct-ion after having first been rotated in the opposite direction to compress the fuel mixture.

Obviously, the ignition systemof this invention may manner, such, as a magnetic coupling.

1 also be used for: starting engines adapted to rotate in one directiononly. In this caseone of the circuitbrea-kers 1 and 2, the preselector 6 and one of the contacts 12 and 13 lee-tor means for activating could be omitted, thelatter being substituted by some 7 other suitable abutment for the contact arm 14. I J

Various other-'modifications of the invention are possi-"' ble within the scope of the appended? claims. Thus, the;

device described may also be applied to engines having more than one cylinder, as will be obvious to those skilled in the art. With some furthermodifications it may} also be applied to diesel engines, in which case the device would have to, control fuel injection rather than'spark pro duction. Therefore, the term ignition.should be under- I stood in-itsbrozadest sense so as to compriseboth the concept of spark-production and the con'ceptof fuel injection.

However; in both cases-the basic principle would be the; same, viz.- that the concluding backward stroke ofthe en-t gine, when stopped,'causes fuel: to be ignited in thecylin-v der inquestiontoidrive th e crankshaft in the reverse direction. Equally, the 'invention could be applied itofour stroke engines, either simply for starting purposes or-"for;

the 'purpose of reversing the runningdirect-ionof the ena gine; Inthe'la-tter case the engine would, of course, have to be provided with: ashi-fitable camshaft having dual cams for controlling the valves, the shifting ofsuch camshaft being itself controlled-by the rocking arm 14, or its equivalent. In the case of four stroke'en-gincs, the rocking.

arm 14 could alternatively be operativelyconnectedwith the camshaft. The frict-ion coupling described. couldube replaced by any other'suit-able coupling acting in a similar 1."An ignition system for internal combustion piston:

at will either of said first and second combustioncontrolling means, and means assoc'iated withisaid selector means for causing combustion of gas compressed in said engine when the latter reverses its direction of rotation underthe act-ion of such compressed gas. I I t i 4. An-ignit-i-on system'for-intemal combustion piston engines, comprising a spark; producingcircuit, circuit breaker means cont-rolling saidcircuit during normal operation of the engine, and additional circuit breaker means control-lingfsaid circuitfor producing a, spark when said enginereyerses itsdirctionofqrotation' under the action of gas compressedin said engine.

5. An ignition system forinternall combustion piston engines, comprising a spark producing circuit, first circuit breakerfmean's for controlling, said vcircuit during running 'lof'the engine in one;direct ion, second circuit breaker means for. controlling said circuit during running" of said.

- engine" in the opposite direction,rm'anually operable se-- lect-or-meansfior connecting" at will either of said first and 'second, circuitbreaker means into said spark producing circuit, and additional circuit breaker means associated with said selector means for controlling said circuit for .producingwa spark When'said engine reverses its direction of rotationunder the'action of gas compressed in said fangme a 7 V 6. An ignition system forfiinternal combustion piston Y engines, comprising .a spark producing circuit, first circuit breaker means for controllingsaid circuit during running of the engine infon'e direction, second circuit breaker meansfor controlling said circuit during running of'said engine in the opposite direction, manually operable selector means for connecting at=will either of said first and engines, comprising in combination means for causingcombustionof gas compressed in the enginefduring normal operation thereof, and means for causing combustion of gas compressed in the engine when the latterreverses 'its direction of rotation under pressed gas, a q p I v t 2. An' ignition system for internal combustion, piston engines, comprising means forcaus'ing combustion of gas compressed in the engine during normal operation thereof,

means mounted for rocking movement and operatively connected with a rotating shaftofsaid engine to assume; 7

the action of such, com-i 1 7 said selector means when' said rockingmeans shifitsffrom either of two extreme positions in accordance with thetdi- Y 'rection of rotation of said shaft, and 'means associated with-said rocking means for causing combustion of gasi compressed in said enginewhen' said rocking'means shifts f t c from one extreme position to the other. 1 v

"3. An ignition system for internal combustion piston engines, comprising first mc'ansfor controlling combustion of I gas com-pressed in the engine at one directionfof rotation or the latter, second means for controllingcombustion of gas compressed insaid engine at the opposite direction of. rotation of the -latter, manually, adjustable sesecond circuit brcake1 -me=ans into said spark producing circuit, means mounted/for rocking movement and operatively connected with a rotating shaft of said engine to- 'RICHARDIB. WILKINSON, Primarys Exz imine r. i a

J. BREcHn xamiaer. J 

1. AN IGNITION SYSTEM FOR INTERNAL COMBUSTION PISTON ENGINES, COMPRISING IN COMBINATION MEANS FOR CAUSING COMBUSTION OF GAS COMPRESSED IN THE ENGINE DURING NORMAL OPERATION THEREOF, AND MEANS FOR CAUSING COMBUSTION OF GAS COMPRESSED IN THE ENGINE WHEN THE LATTER REVERSES ITS DIRECTION OF ROTATION UNDER THE ACTION OF SUCH COMPRESSED GAS. 